Hi,
Thanks for checking out my boot loader!
About your issue, @Octocontrabass is perfectly right in everything. You are looking at the code which locates the initrd in a ROM image. The disk storage code starts
at line 1030.
The error message you're getting means one of these:
1. you probably have a valid GPT, otherwise the message would be "no gpt found", line 1041
2. in the GPT there's no partition with bootable flag set (EFI_PART_USED_BY_OS, attrib bit 2). This is optional to let you choose a partition explicitly, line 1063
3. if there's no partition flagged, then there's no partition with ESP UUID either (most likely this is your problem), line 1072
4. if partition found, it does not contain a FAT file system (the code explicitly checks for "FAT16" and "FAT32" magic bytes in the BPB), line 1108
5. the FAT partition does not contain a directory named "BOOTBOOT" in it's root directory, line 1203
Please note that due to licensing issues, the loader only uses 8+3 MSDOS file names, so if you have only LFN entry for the BOOTBOOT directory, it won't be able to find it (some fs creators are only saving the LFN entry to avoid these licensing issues).
It is not the case here, but be aware that there's an unresolved issue with some compressed initrd in the BIOS implementation, not all images are handled properly (I didn't had the time to debug this yet but I'm on it. With the RPi and EFI versions all compressed images work without a problem, but for the BIOS version there's a 50%-50% chance that it can't be uncompressed. If you want to use the BIOS version, I'd recommend uncompressed initrd images only for the time being).
Cheers,
bzt